Field of the Invention
This invention relates to a gimbal assembly of a single or dual-stage actuator, and more specifically to a tongue/dimple interface which uses gold to reduce fretting wear.
Description of the Related Art
In a hard disk drive assembly, a magnetic recording head gimbal assembly provides the freedom for the head to move over the contours of the disk and accommodate disk drive assembly tolerances. This gimbal assemble of the read/write head permits the head to move from track to track over a platter on which data is stored. Because of continuous motion and variation in the drive assembly, the gimbal interface between the dimple and the tongue is in constant relative motion. To further complicate the motion of this interface a second or dual stage actuation may also be introduced. The dual stage actuator provides additional finer actuation, or movement, A finer level of movement may be achieved at a tip of the head, or slider, usually as a result of a piezoelectric transducer (PZT) mechanism. Activation of the PZT is translated into movement of the slider, and this permits finer movement across tracks on the platter. This allows tracks to be spaced closer together, thus enabling more data to be stored on a platter.
A hard disk drive magnetic recording head gimbal assembly has the magnetic recording head, or slider, suspended over the disk media material by a suspension containing a gimbal for the slider. Conventional gimbals use a stainless steel foil formed into a dimple that contacts a flat stainless steel tongue. The slider body is rigidly bonded to the tongue and the slider, and then is able to rotate, or “gimbal,” about the dimple surface at a tongue/dimple interface. Both the tongue and dimple are made of stainless steel which wear together during suspension assembly, head gimbal assembly, head stack assembly, disk drive assembly and disk drive operation. When the dimple and tongue wear together, wear particles are generated that may be harmful to the disk drive. The wear particles are generated by what is known as fretting or tribo chemical corrosion (tribocorrosion), the combined effects of wear and corrosion. In the case of the contact between the tongue and dimple, the tribocorrosion is due to the exposure of iron to oxygen, and, along with fretting wear, results in iron oxide wear particles which are typically a hard, flaky substance. The amount of wear particles must be carefully measured during testing, as a large amount of wear particles is believed to be a cause of degraded performance of the hard drive and even complete hard drive failure.